Commit 58761221 authored by Dan Elphick's avatar Dan Elphick Committed by Commit Bot

[parser] Delete unresolved variables created for labels

This deletes unresolved VariableProxy objects created for labels in the
preparser which prevents shadowed variables in enclosing scopes from
being context-allocated.

Previously this was only done in the full parser, which leads to
bytecode mismatches with lazy source positions.

Bug: chromium:1009728, v8:8510
Change-Id: If2d0c345346116a7f5aacbcd0cf3638e9f7e04cc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1836258Reviewed-by: 's avatarSathya Gunasekaran  <gsathya@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64104}
parent 2d847f8d
......@@ -1402,6 +1402,7 @@ void Scope::AnalyzePartially(DeclarationScope* max_outer_scope,
for (VariableProxy* proxy = scope->unresolved_list_.first();
proxy != nullptr; proxy = proxy->next_unresolved()) {
if (proxy->is_removed_from_unresolved()) continue;
DCHECK(!proxy->is_resolved());
Variable* var =
Lookup<kParsedScope>(proxy, scope, max_outer_scope->outer_scope());
......
......@@ -548,6 +548,10 @@ class ExpressionParsingScope : public ExpressionScope<Types> {
return end;
}
ScopedList<std::pair<VariableProxy*, int>>* variable_list() {
return &variable_list_;
}
protected:
bool is_verified() const {
#ifdef DEBUG
......@@ -559,10 +563,6 @@ class ExpressionParsingScope : public ExpressionScope<Types> {
void ValidatePattern() { Validate(kPatternIndex); }
ScopedList<std::pair<VariableProxy*, int>>* variable_list() {
return &variable_list_;
}
private:
friend class AccumulationScope<Types>;
......
......@@ -5135,20 +5135,37 @@ ParserBase<Impl>::ParseExpressionOrLabelledStatement(
}
bool starts_with_identifier = peek_any_identifier();
ExpressionT expr = ParseExpression();
if (peek() == Token::COLON && starts_with_identifier &&
impl()->IsIdentifier(expr)) {
// The whole expression was a single identifier, and not, e.g.,
// something starting with an identifier or a parenthesized identifier.
impl()->DeclareLabel(&labels, &own_labels,
impl()->AsIdentifierExpression(expr));
Consume(Token::COLON);
// ES#sec-labelled-function-declarations Labelled Function Declarations
if (peek() == Token::FUNCTION && is_sloppy(language_mode()) &&
allow_function == kAllowLabelledFunctionStatement) {
return ParseFunctionDeclaration();
}
return ParseStatement(labels, own_labels, allow_function);
ExpressionT expr;
{
// Effectively inlines ParseExpression, so potential labels can be extracted
// from expression_scope.
ExpressionParsingScope expression_scope(impl());
AcceptINScope scope(this, true);
expr = ParseExpressionCoverGrammar();
expression_scope.ValidateExpression();
if (peek() == Token::COLON && starts_with_identifier &&
impl()->IsIdentifier(expr)) {
// The whole expression was a single identifier, and not, e.g.,
// something starting with an identifier or a parenthesized identifier.
DCHECK_EQ(expression_scope.variable_list()->length(), 1);
VariableProxy* label = expression_scope.variable_list()->at(0).first;
impl()->DeclareLabel(&labels, &own_labels, label->raw_name());
// Remove the "ghost" variable that turned out to be a label from the top
// scope. This way, we don't try to resolve it during the scope
// processing.
this->scope()->DeleteUnresolved(label);
Consume(Token::COLON);
// ES#sec-labelled-function-declarations Labelled Function Declarations
if (peek() == Token::FUNCTION && is_sloppy(language_mode()) &&
allow_function == kAllowLabelledFunctionStatement) {
return ParseFunctionDeclaration();
}
return ParseStatement(labels, own_labels, allow_function);
}
}
// If we have an extension, we allow a native function declaration.
......
......@@ -1523,15 +1523,11 @@ Statement* Parser::DeclareNative(const AstRawString* name, int pos) {
void Parser::DeclareLabel(ZonePtrList<const AstRawString>** labels,
ZonePtrList<const AstRawString>** own_labels,
VariableProxy* var) {
DCHECK(IsIdentifier(var));
const AstRawString* label = var->raw_name();
// TODO(1240780): We don't check for redeclaration of labels
// during preparsing since keeping track of the set of active
// labels requires nontrivial changes to the way scopes are
// structured. However, these are probably changes we want to
// make later anyway so we should go back and fix this then.
const AstRawString* label) {
// TODO(1240780): We don't check for redeclaration of labels during preparsing
// since keeping track of the set of active labels requires nontrivial changes
// to the way scopes are structured. However, these are probably changes we
// want to make later anyway so we should go back and fix this then.
if (ContainsLabel(*labels, label) || TargetStackContainsLabel(label)) {
ReportMessage(MessageTemplate::kLabelRedeclaration, label);
return;
......@@ -1549,11 +1545,6 @@ void Parser::DeclareLabel(ZonePtrList<const AstRawString>** labels,
}
(*labels)->Add(label, zone());
(*own_labels)->Add(label, zone());
// Remove the "ghost" variable that turned out to be a label
// from the top scope. This way, we don't try to resolve it
// during the scope processing.
scope()->DeleteUnresolved(var);
}
bool Parser::ContainsLabel(ZonePtrList<const AstRawString>* labels,
......
......@@ -8,6 +8,7 @@
#include <cstddef>
#include "src/ast/ast-source-ranges.h"
#include "src/ast/ast-value-factory.h"
#include "src/ast/ast.h"
#include "src/ast/scopes.h"
#include "src/base/compiler-specific.h"
......@@ -274,7 +275,7 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
Statement* BuildInitializationBlock(DeclarationParsingResult* parsing_result);
void DeclareLabel(ZonePtrList<const AstRawString>** labels,
ZonePtrList<const AstRawString>** own_labels,
VariableProxy* expr);
const AstRawString* label);
bool ContainsLabel(ZonePtrList<const AstRawString>* labels,
const AstRawString* label);
Expression* RewriteReturn(Expression* return_value, int pos);
......
......@@ -5,6 +5,7 @@
#ifndef V8_PARSING_PREPARSER_H_
#define V8_PARSING_PREPARSER_H_
#include "src/ast/ast-value-factory.h"
#include "src/ast/ast.h"
#include "src/ast/scopes.h"
#include "src/parsing/parser-base.h"
......@@ -1071,9 +1072,8 @@ class PreParser : public ParserBase<PreParser> {
V8_INLINE void DeclareLabel(ZonePtrList<const AstRawString>** labels,
ZonePtrList<const AstRawString>** own_labels,
const PreParserExpression& expr) {
DCHECK(!parsing_module_ || !expr.AsIdentifier().IsAwait());
DCHECK(IsIdentifier(expr));
const AstRawString* label) {
DCHECK(!parsing_module_);
}
// TODO(nikolaos): The preparser currently does not keep track of labels.
......
// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --stress-lazy-source-positions
function foo(x) {
(function bar() {
{
x: 1
}
function f() {}
});
}
foo();
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